Bleaching agent

ABSTRACT

The invention relates to particles comprising a peroxy compound with capability of releasing hydrogen peroxide or peroxy acids in aqueous solutions and up to 15% by weight of a dicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof. The invention also relates to use of the particles and a composition comprising such particles.

The present invention relates to particles comprising a peroxy compoundand a dicarboxylic acid having from 5 to 10 carbon atoms or a saltthereof. The invention also relates to use of the particles and acomposition containing such particles.

Powder detergent compositions often contain peroxy compounds asbleaching agents which release hydrogen peroxide or peroxy acids inaqueous solutions. However, many peroxy compounds are not storaaestable. Their decomposition is supposed to be catalysed by metal cationsmoving comparatively freely through the water normally being present indetergents, but is also facilitated by the alkaline pH (normally fromabout 8 to about 12) and by other components commonly present indetergents, for example zeolites or bleaching activators such as TAED(tetraacetylethylene diamine), TAGU (tetraacetylglucoluril) or PAG(penta acetyl glucose)

In order to make environmental friendly detergents, it is desirable touse alkali metal carbonate peroxy hydrate, commonly known aspercarbonate, as a bleaching agent. However, the activity ofpercarbonate in a detergent decreases rapidly through decomposition ifthe detergent is stored at normal room temperature and humidity.

Many attempts to stabilize percarbonate have been done, for example bymixing or coating with stabilizing substances such as sulfates,carbonates, borates, silicates or organic substances. Such stabilizingmethods are described in the patent literature, for example in GB1466799, GB 1538893, GE 1575792, EP 459625, U.S. Pat. No.3,975,280 andEP 573731.

U.S. Pat. No.4,075,116 describes preparation of percarbonate from sodiumcarbonate, hydrogen peroxide and different additives.

CH patent 659082 describes mixing bleaching agents with high amounts ofinorganic carbonates and water soluble acids and thereby increasing thedissolution rate.

Japanese laid open patent application (Kokai) Sho 58-74508 describes amixing percarbonate with silicate and phosphate, borate, citrate,tartrate or succinate of sodium and thereby increasing the dissolutionrate.

U.S. Pat. No. 5,340,496 describes stabilization of percarbonate withcertain combinations of inorganic salts and carboxylic acids,particularly long chained acids such as oleic acid.

The object of the present invention is to provide particles comprising aperoxy compound, particularly alkali metal percarbonate, with improvedstorage stability, particularly in detergent compositions. It is anotherobject of the invention to provide particles comprising a peroxycompound only containing environmental friendly constituents.

Through the present invention, these objects has been fulfilled byproviding particles comprising a peroxy compound with capability ofreleasing hydrogen peroxide or peroxy acids in aqueous solutions, theparticles further comprising up to 15% by weight, preferably up to about10% by weight, most preferably up to about 5% by weight of a preferablywater soluble dicarboxylic acid having from 5 to 10 carbon atoms or asalt thereof. The particles preferably comprise more than about 0.01% byweight, most preferably more than about 0.05% by weight of such adicarboxylic acid or a salt thereof. The amount of the peroxy compoundin the particles is suitably from about 10 to about 99% by weight,preferably more than 50% by weight and most preferably up to about 95%by weight. The dicarboxylic acid in the particles may be mixed with theperoxy compound and/or be included in a coating.

It is assumed that the dicarboxylic acid acts as a chelating agent, butit has surprisingly been found that the dicarboxylic acids according tothe invention gives superior storage stability compared to conventionalchelating agents such as EDTA. Too high a concentration of dicarboxylicacids or salts thereof will however decrease the thermal stability,particularly at high concentrations of the peroxy compounds.

It is preferred to use an alkali metal or an alkaline earth metal saltof the dicarboxylic acid. Alkali metals are preferably selected fromsodium, potassium or mixtures thereof, and alkaline earth metals arepreferably selected from calcium, magnesium or mixtures thereof. Sodiumsalts are particularly preferred. In the following description of theinvention, the term dicarboxylic acid also refers to salts thereof.

Suitably, the dicarboxylic acid comprises from 5 to 8 carbon atoms,preferably 5 to 7 carbon atoms. Preferably, the carboxylic acid groupsare located at the ends of the carbon chain. Further, the dicarboxylicacid preferably does not comprise any hydroxyl groups and mostpreferably it does not comprise any functional groups except thecarboxylic acid groups.

The most preferred dicarboxylic acids satisfy the formula:

    COOH--R--COOH

in which R is alkylene, which is preferred, or alkenylene, having from 3to 8 carbon atoms, preferably from 3 to 5 carbon atoms. Preferably, R isa straight chain without branches.

Examples of useful dicarboxylic acids are glutaric acid adipic acid,pimelic acid, suberic acid, azelaic acid, sebacic acid and mixturesthereof, of which glutaric acid, adipic acid and pimelic acid areparticularly preferred. Glutaric acsa is the most preferred acid.

It is to be understood that the particles may include two or moredifferent dicarboxylic acids as described herein.

The particles may also include other environmentally acceptablestabilizers or inert substances.

The particles preferably contain silicate which further improves tnestability and also enhances the mechanical strength. Silicate may bemixed with the peroxy compound and/or be included in a coating.Preferably at least some of the silicate is mixed with the peroxycompound. The silicate is suitably an alkali metal silicate, preferablyof sodium, potassium or mixtures thereof, most preferably of sodium. Themolar ratio SiO₂ :M₂ O, M being an alkali metal, is preferably fromabout 1 to about 3, most preferably from about 1 to about 2.5. Theparticles suitably contains from about 0.1 to about 20% by weight,preferably from about 0.2 to about 15% by weight, most preferably fromabout 0.5 to about 10% by weight of silicate expressed as sodiumsilicate.

It has been found that the stability is further improved if theparticles contain a water soluble magnesium compound, preferablymagnesium sulfate. The magnesium compound may be mixed with the peroxycompound and/or be included in a coating. Preferably at least some ofthe magnesium is mixed with the peroxy compound, most preferably incombination with alkali metal silicate. The particles preferablycontains from about 0.01 to about 50 by weight, most preferably fromabout 0.1 to about 3% by weight of magnesium compounds expressed asmagnesium sulfate.

According to an embodiment of the invention, it has been found that asynergistic effect appears if the particles also comprise a chelatingagent selected from hydroxy carboxylic acids satisfying the formula:

    R'C.sub.n H.sub.m (OH).sub.n COOH

in which R' is CH₂ OH or COOH, n is 2-6, and m is 0-n; or salts thereof.

It is preferred to use an alkali metal or an alkaline earth metal saltof the hydroxy carboxylic acid. Alkali metals are preferably selectedfrom sodium, potassium or mixtures thereof, and alkaline earth metalsare preferably selected from calcium, magnesium or mixtures thereof.Sodium salts are particularly preferred. in the following description ofthe invention, the term hydroxy carboxylic acid also refers to saltsthereof.

The particles preferably contain from about 0.01 to about 15% by weight,most preferably from about 0.01 to about 10% by weight, particularlypreferably from about 0.05 to about 5% by weight of hydroxy carboxylicacids of the above formula. The weight ratio dicarboxylic acid tohydroxy carboxylic acid is preferably from about 0.05:1 to about 4:1,most preferably from about 0.1:1 to about 1:1. The hydroxy carboxylicacid may be mixed with the peroxy compound and/or be included in acoating.

Preferably R' in the above formula is CH₂ OH. It is also preferred thatn is 4 or 5. Preferably, m is equal to n or n-2, the carbon chain thusbeing saturated or containing one double bond. A particularly preferredsalt of a hydroxy carboxylic acid is alkali metal glucoheptonate (R' isCH₂ OH, n and m are 5). Other preferred salts of hydroxy carboxylicacids are alkali metal gluconate (R' is CH₂ OH, n and m are 4) andalkali metal ascorbate (R' is CH₂ OH, n is 4 and m is 2). Other usefulhydroxy carboxylic acids include, for example, trihydroxy glutaric acid,tartaric acid or saccharic acid. It is to be understood that theparticles may include two or more different hydroxy carboxylic acids ofthe above formula.

Particles according to the invention have high stability even ifuncoated, but the highest stability is normally achieved if theparticles are coated. Such a coating may for example contain one or moredicarboxylic acid as described herein, hydroxy carboxylic acids asdescribed herein, alkali metal silicate, water soluble magnesiumcompounds such as magnesium sulfate, alkali metal salts of carbonate,bicarbonate or sulfate, or environmental acceptable organic chelatingagents, the different components being applied in one or several layers.

In one embodiment of the invention, a dicarboxylic acid as describedherein is only present as mixed with the peroxy compound while a hydroxycarboxylic acid as described herein is only present in a coating, orvice versa.

In another embodiment both a dicarboxylic acid as described herein and ahydroxy carboxylic acid as described herein are mixed with the peroxycompound and/or are included in a coating.

Suitably, the particles have an average diameter From about 50 to about3000 μm, preferably from about 100 to about 1600 μm. The preferreddensity is from about 600 to about 1500 g/l, particularly from about 800to about 1100 g/l. It has been found that a high density as well as ahigh average particle size improves the storage stability.

The invention is particularly advantageous if the peroxy compound isalkali metal percarbonate, but also other peroxy compounds can bestabilized, for example alkali metal salts of perborates,peroxysulfates, peroxyphosphates or peroxysilicates, peroxycarboxylicacids or peroxycarboxylic acid releasing compounds such as di-acylateddi-peroxy carboxylic acids (see WO 91/17143).

Particles according to the invention can be prepared by conventionalmethods. Ingredients to be mixed with the peroxy compound are preferablyadded in a granulation step, but may also be included directly when, forexample, alkali metal percarbonate is produced from alkali metalcarbonate and hydrogen peroxide. If alkali metal silicate is to beincluded, it is preferably added in the form of an aqueous solution, andthe dicarboxylic acid or a salt thereof and optionally a hydroxycarboxylic acid or a salt thereof is then preferably mixed thereinbefore addition to the peroxy compound. Granulation may be performed byconventional methods well known among those skilled in the art, such ascompacting, extruding, agglomeration in drum or disk, fluid-bedgranulation, prilling or in different kinds of mixers. An optionalcoating step may be performed by spraying the particles with preferablyaqueous solutions of the components to be applied, for example in a drumor a fluid bed.

The invention further concerns use of the described particles comprisinga peroxy compound and a dicarboxylic acid as a bleaching agent,preferably in connection with washing of textiles or dishwashing. Thewashing water may be supplied with particles according to the inventionbeing included in a detergent composition or being in the form of aseparate bleaching powder. Preferably, washing water is supplied withparticles in an amount so to obtain from about 0.001 to about 1 gramactive oxygen per liter, which for example corresponds to from about0.01 to about 6 grams sodium percarbonate.

Finally, the invention concerns a ccmuosition containing an inertfiller, and/or one or several substances active at washing, whichcomposition further contains particles comprising a peroxy compound anda dicarboxylic acid according to the invention, for example in an amountfrom about 1 up to about almost 100% by weight. The composition maycomprise a mixture of particles containing different kinds of peroxycompounds. The substances active at washing may include detergentbuilders, surfactants, alkali generating substances, bleachingactivators, enzymes, or any other substances commonly used indetergents. The detergent builder may for example be selected fromphosphates such as tripolyphosphates, pyrophosphates or orthophosphatesof alkali metals or ammonium, zeolites such as Zeolite A (e.g. Zeolite4A), Zeolite B, Zeolite P, Zeolite X, or Zeolite HS, Zeolite MAP,silicates such crystalline layered disilicates (e.g. of the formulaNaMSI_(x+1) ·yH₂ O wherein M is sodium or hydrogen, x is a number from1.9 to 4 and y is a number from 0 to 20), amorphous disilicates (e.g.Britesil™) polycarboxylates, citrates, carbonates, bicarbonates,sesquicarbonates, sulfates, borates or mixtures thereof. The surfactantsare preferably selected from anionic surfactants, nonionic surfactants,soaps or mixtures thereof. Anionic surfactants may for example beselected from linear alkylbenzene sulfonates, secondary alkanesulfonates, alpha-sulfonated methyl fatty acid esters, alkylsulfates,alcohol-ethoxysulfates, alpha-olefine sulfonates, alkali metalsarcosinates or alkyl ester sulfonates. Nonionic surfactants may forexample be selected from alkoxylated compounds such as fatty alcohols,alkylphenols and alkylamines or from alkyl polyglucosides or polyhydroxyfatty acid amides. Soaps may for example be selected from sodium orpotassium salts of tallow. Also cationic surfactants such as quaternaryammonium compounds or imide azolinium salts, as well as amphotericsurfactants might be used. Alkali generating substances may for examplebe selected from carbonates, silicates, phosphates or mixtures thereof.The bleaching activators may for example be selected from N- orO-acylated compounds such as TAED, TAGU, SNOBS (sodium nonoyl benzenesulfonate), PAG (penta acetyl glucose) or diacylated diperoxy carboxylicacids (see WO 91/17143). The feller may include any inert substance suchas sodium sulfate. The composition may constitute a complete detergentor a bleaching powder to be added separately at washing. The enzymes mayfor example be selected from amylases, neutral and alkaline proteases,lipases, esterases or cellulases.

A complete detergent for washing of textiles suitably contains fromabout 1 to about 40% by weight, preferably from about 10 to about 30% byweight of particles according to the invention. Further, the detergentsuitably contains a detergent builder, for example from about 5 to about50% by weight, surfactants, for example from about 5 to about 35% byweight and an alkali generating substance, for example from about 5 toabout 20% by weight. Preferably, the detergent contains from about 5 toabout 20% by weight of anionic surfactants, from about 2 to about 15% byweight of nonionic surfactants, and from about 0.1 to about 5% by weightof soaps. The detergent may also contain bleaching activators, forexample from about 1 to about 10% by weight, enzymes, for example fromabout 0.5 to about 2.5% by weight, and fillers such as sodium sulfate,for example from about 5 to about 50% by weight. It is also possible toinclude chelating agents such as phosphonates, EDTA, NTA (nitrilotriacetic acid), iminodiacetic acid derivatives or EDDS(ethylenediamine-N,N-disuccinic acid, for example in an amount fromabout 0.1 to about 1% by weight. Additionally, the detergent may containconventional components such as water glass, carboxy methyl cellulose,dispersants such as homo or copolymers of polycarboxylic acids, foamregulators, antioxidants, perfumes, colouring agents, opticalbrighteners and water (normally from about 3 to about 15% by weight).The detergent can be prepared with conventional methods such as drymixing, agglomeration or spray drying. If the preparation involves spraydrying, any heat sensible component such as particles comprising peroxycompounds, enzymes and perfumes should be added to the dried material.

A separate bleaching powder may comprise up to almost 100% by weigh: ofparticles containing peroxy compounds according to the invention, butpreferably the content is from about 5 to about 90% by weight. Thebleaching powder may comprise only one peroxy compound or a mixture ofparticles containing different kinds of peroxy compounds. It isadvantageous if a hydrogen peroxide generating substance such aspercarbonate, for example from about 10 to about 75% by weight, is usedin combination with a bleaching activator such as TAED or TAGU, forexample from about 2 to about 25% by weight. Also other bleachingactivators such as a diacylated dipercarboxylic acid may be used, forexample in an amount from about 2 to about 25% by weight. A bleachingpowder may also contain detergent builders, for example from about 5 toabout 90% by weight, surfactants, for example up to about 10% by weight,enzymes, for example up to about 2% by weight, or fillers, for examplefrom about 5 to about 90% by weight. A preferred bleaching powderconsists essentially of from about 30 to about 75% by weight ofparticles containing percarbonate, from about 10 to about 25% by weightof a bleaching activator, the balance preferably substantially beingdetergent builders, fillers, surfactants, water or mixtures thereof.

A detergent for dishwashing may be in the form of a low alkalinedetergent (pH of washing water intended to be about 10-11) suitablycontaining from about 2 to about 15%; by weight of a bleaching agentcomprising particles according to the invention, from about 5 to about50% by weight of alkali metal disilicate, from 0 to about 40% by weightof alkali metal carbonate, from about 15 to about 50% by weight ofbuilders such as sodium citrate and polycarboxylates or sodium tripolyphosphate (STPP), from about 0.5 to about 5% by weight of lowfoaming nonionic surfactants, from about 0.5 to about 5% by weight ofenzymes and from about 1 to about 6% by weight of bleaching activatorssuch as TAED. A dishwasher detergent may also be high alkaline (pH ofwashing water intended to be about 11-12) having a similar compositionas the low alkaline detergent, the disilicate however being replacedwith from about 20 to about 80% by weight of alkali metal metasilicateand the builder preferably substantially consisting of STPP.

The present invention makes it possible to prepare stable bleachingagents comprising peroxy compounds, particularly percarbonate, which maybe used in detergents including zeolites such as zeolite 4A. Theinvention also makes it possible to decrease or exclude the use of forexample EDTA or phosphonates which are less suitable from anenvironmental point of view.

The invention will now be described through the following exampleswhich, however, not are intended to limit the scope of the invention. Ifnot otherwise stated, all contents an percentages refer to content andpercent by weight based on the entire particle.

EXAMPLE 1

Sodium percarbonate particles with a diameter of about 315-1250 μm and adensity of about 900 g/l were prepared by granulating fine percarbonateparticles in a rotating Eirich drum together with different additivessupplied as aqueous solutions and drying the granules in a fluidizedbed. In order to test the storage stability of the percarbonate, theprepared particles as well as reference particles of pure sodiumpercarbonate were included in a standard detergent IEC-Z (Henkel)consisting of 9.7% linear alkyl benzenesulfonate (C_(average) 11.5),5.2% ethoxylated C₁₂₋₁₈ alcohol (EO₇), 3.6% sodium-soap, 32.5% zeolite4A, 11.8% sodium carbonate, 5.2% sodium salt of copolymerisate ofacrylic- and maleic acid (Sokolan CP₅), 3.4% sodium waterglass (ratio3.3), 1.3% carboxy methyl cellulose, 0.3% EDTA, 0.3% optical brightener(stilbene type), 7.4% sodium sulfate, 12.2% water, 6.5% foam inhibitor(SIK), 0.5% enzyme prills protease (activity 300.00). Samples wereprepared from 64 grams IEC-Z, 12 grams percarbonate particles and 4grams TAED. A Quick Stability Index (QSI) was determined for each sampleby measuring the amount of oxygen formed during 24 hours storage at 40°C. and dividing the amount oxygen liberated by the relative content (%)of active oxygen in the original percarbonate. Thus, a low QSI-valuemeans high stability. The results appear in the table below, in whichthe contents of the different constituents refer to % by weight based onthe entire particle. The following abbreviations are used: SPC=sodiumpercarbonate; GA=sodium salt of glutaric acid; GH=sodium glucoheptonate;AA=sodium salt of adipic acid; PA=sodium salt of pimelic acid;SDS=sodium disilicate; AO=active oxygen; QSI=cuick stability index.

    ______________________________________                                        SPC     GA        AA     PA     AO    QSI                                     ______________________________________                                        100%    --        --     --     14.5% 5.66                                    98%     2%        --     --     14.1% 2.64                                    98%     --        -2%    --     14.3  2.09                                    98%     --        --     2%     14.1% 2.38                                    ______________________________________                                    

EXAMPLE 2

Sodium percarbonate were prepared and tested as in Example 1. Theresults appear in the table below:

    ______________________________________                                        SPC    GA     GH       SDS  MgSO.sub.4                                                                            AO    QSI                                 ______________________________________                                        97.2%  1.5%   --       1.2% 0.1%    14.0% 2.28                                97.2%  --     1.5%     1.2% 0.1%    14.0% 2.59                                97.2%  0.5%   1.0%     1.2% 0.1%    14.1% 1.63                                97.2%  1.0%   0.5%     1.2% 0.1%    14.1% 2.14                                ______________________________________                                    

EXAMPLE 3

Sodium percarbonate particles with a diameter of about 315-1250 μm and adensity of about 900 g/l were prepared by granulation from finepercarbonate particles together with sodium salt of glutaric acid,sodium disilicate and magnesium sulfate supplied as aqueous solutions.The granulation was performed by extruding a mixture of the ingredients,crushing the string formed, rounding the particles obtained on arotating disk and drying and sieving the rounded particles. Forcomparative purposes one sample was prepared without glutaric acid andone sample was prepared with EDTA instead of glutaric acid. Thestability of the particles was tested in a standard IEC-Z detergent inthe same way as in Example 1 and the results appear in the table below.

    ______________________________________                                        SPC    GA     EDTA     SDS   MgSO.sub.4                                                                           AO    QSI                                 ______________________________________                                        99.2%  --     --       0.67% 0.12%  14.3% 3.4                                 99.0%  --     0.2%     0.67% 0.12%  14.4% 3.1                                 99.0%  0.2%   --       0.67% 0.12%  14.4% 2.6                                 98.8%  0.5%   --       0.63% 0.12%  14.2% 2.1                                 ______________________________________                                    

EXAMPLE 4

Sodium percarbonate particles with a diameter of 315-1250 μm were coatedwith sodium salts of glutaric acid and/or glucoheptonic acid applied asaqueous solutions by spraying in a fluidized bed. For comparativepurposes particles were also coated with benzoic acid and caproic acid.The stability of the particles was tested in a standard IEC-Z detergentin the same way as in Example 1 and the results appear in the tablebelow.

    ______________________________________                                        SPC        GA     GH         AO    QSI                                        ______________________________________                                        100%       --     --         14.5% 5.66                                       95%        5%     --         13.6% 0.65                                       95%        --     5%         13.9% 0.78                                       95%        4%     1%         13.6% 0.40                                       95%        3%     2%         13.4% 0.31                                       95%        2%     3%         13.3% 0.25                                       95%        1%     4%         13.6% 0.31                                       95%        5% benzoic acid   13.8% 2.31                                       95%        5% caproic acid   13.9% 2.27                                       ______________________________________                                    

EXAMPLE 5

Sodium percarbonate particles with a diameter of 315-1250 μm were coatedby spraying in a fluidized bed with a first aqueous solution of sodiumsilicate (SiO₂ :Na₂ O ratio 1), sodium glucoheptonate and/or sodium saltof glutaric acid, and a second solution of magnesium sulfate andoptionally sodium sulfate or sodium bicarbonate. In one experiment athird solution of sodium carbonate was applied. The stability of theparticles was tested in a IEC-Z detergent in the same way as in Example1 and the results appear in the table below:

    ______________________________________                                                   Exp. 1                                                                              Exp. 2    Exp. 3  Exp. 4                                     ______________________________________                                        sodium percarbonate                                                                        85.1%   85.1%     85.1% 85.1%                                    glucoheptonic acid                                                                         --      0.75%     0.75% 0.75%                                    glutaric acid                                                                              1.5%    0.75%     0.75% 0.75%                                    sodium disilicate                                                                          2%      2%        2%    2%                                       MgSO.sub.4   1.4%    1.4%      1.4%  1.4%                                     Na.sub.2 SO.sub.4                                                                          10%     10%             --                                       NaHCO.sub.3  --      --        10%   --                                       Na.sub.2 CO.sub.3                                                                          --      --        --    10%                                      active oxygen                                                                              12.8%   12.9%     12.8% 12.8%                                    QSI          0.28    0.22      0     0.16                                     ______________________________________                                    

EXAMPLE 6

Sodium percarbonate parzicles prepared by granulation as in Example 3contained 98.8% sodium percarbonate, 0.12% MgSO₄, 0.63% sodiumdisilicate, 0.5% gluzaric acid (as sodium salt), and had a content ofactive oxygen of 14.2%. The particles were coated as in Examples 5 with1.4% MgSO₄, 2% sodium disilicate, 10% Na₂ CO₃, and 1% glutaric acid (assodium salt). The coated particles contained 12.6% of active oxygen. Thestability of the particles was tested in a IEC-Z detergent in the sameway as in Example I and it was found that QSI for the uncoated particleswas 2.20 and QSI for the coated particles was 0.04.

We claim:
 1. Particles comprising a peroxy compound with capability ofreleasing hydrogen peroxide or peroxy acids in aqueous solutions,wherein the particles comprise from about 0.01 to 15% by weight of adicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof. 2.Particles as claimed in claim 1, comprising up to about 10% by weight ofa dicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof.3. Particles as claimed in claim 1, wherein the particles comprise analkali metal or alkaline earth metal salt of a dicarboxylic acid havingfrom 5 to 10 carbon atoms.
 4. Particles as claimed in claim 1, wherein adicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof ismixed with the peroxy compound.
 5. Particles as claimed in claim 4,wherein the peroxy compound and the dicarboxylic acid are granulatedtogether.
 6. Particles as claimed in claim 1, wherein a dicarboxylicacid having 5 to 10 carbon atoms or a salt thereof is included in acoating.
 7. Particles as claimed in claim 1 wherein the dicarboxylicacid satisfies the formula:

    COOH--R--COOH

in which R is alkylene or alkenylene having from 3 to 8 carbon atoms. 8.Particles as claimed in claim 7, wherein R is a straight chain withoutbranches.
 9. Particles as claimed in claim 8, wherein the dicarboxylicacid is selected from the group consisting of glutaric acid, adipicacid, pimelic acid, suberic acid, azelaic acid, sebacic acid andmixtures thereof.
 10. Particles as claimed in claim 9, wherein thedicarboxylic acid is glutaric acid.
 11. Particles as claimed in claim 1,wherein the particles further comprise silicate.
 12. Particles asclaimed in claim 11, wherein the particles further comprise alkali metalsilicate.
 13. Particles as claimed in claim 11, wherein the silicate ismixed with the peroxy compound.
 14. Particles as claimed in claim 11,wherein the silicate is included in a coating.
 15. Particles as claimedin claim 1, wherein the particles further comprise a water solublemagnesium compound.
 16. Particles as claimed in claim 1, wherein theparticles further comprise a hydroxycarboxylic acid having the formula:

    R' C.sub.n H.sub.m (OH).sub.n COOH

in which R' is CH₂ OH or COOH, n is 2-6, and m is 0-n; or salts thereof.17. Particles as claimed in claim 16, wherein R' is CH₂ OH, n is 4 or 5,and m is equal to n or n-2.
 18. Particles as claimed in claim 17,wherein the hydroxy carboxylic acid is glucoheptonic acid.
 19. Particlesas claimed in claim 16, wherein a hydroxy carboxylic acid or a salt ismixed with the peroxy compound.
 20. Particles as claimed in claim 16 ,wherein the hydroxy carboxylic acid or a salt is included in a coating.21. Particles as claimed in claim 16, wherein a dicarboxylic acid havingfrom 5 to 10 carbon atoms and a hydroxy carboxylic acid are both mixedwith the peroxy compound.
 22. Particles as claimed in claim 16, whereina dicarboxylic acid having from 5 to 10 carbon atoms and a hydroxycarboxylic acid are both included in a coating.
 23. Particles as claimedin claim 1, wherein the peroxy compound is alkali metal percarbonate.24. Particles as claimed in claim 1, wherein the bulk density is fromabout 800 to about 1500 g/l.
 25. Particles as claimed in claim 24,wherein the bulk density is from about 800 to about 1100 g/l.
 26. Amethod for bleaching an article, comprising washing the article with adetergent containing particles as claimed in claim
 1. 27. A compositioncomprising at least one of an inert filler, or one or several substancesactive at washing, which composition further contains particlesaccording to claim
 1. 28. A detergent composition comprising particlesaccording to claim
 1. 29. A detergent composition as claimed in claim28, wherein it comprises zeolite as a builder.